Method for transmitting/receiving media and device for transmitting/receiving using same

ABSTRACT

Methods and apparatuses for transmitting/receiving a media transport stream by using an internet protocol (IP) based transport system are provided. The transmitting method includes removing some data from media transport stream to be transmitted; configuring at least one entry box including information for reinserting the removed data into the media transport stream; configuring a media data (mdat) box including the media transport stream from which the data has been removed; and positioning and transporting a compression information box including the at least one entry box before the mdat box.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to U.S. provisional Application No. 61/365,372 (filed on Jul.19, 2010), and PCT Application No. PCT/KR2011/005305 (filed on Jul. 19,2011) which are hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to methods and apparatuses fortransmitting/receiving media transport streams by using an internetprotocol (IP) based transport system.

Currently, most of digital broadcasting systems such as terrestrial,cable, or digital multimedia broadcasting systems are streaming AVcontents by using an MPEG-2 transport stream (TS).

In addition, as the internet recently grows rapidly, multimedia servicesthat provide contents by using an internet protocol (IP) network as amain transport network are being activated. Digital broadcasting isdeveloping to an aspect requiring more traffic, such as stereo 3D video,ultra high definition (UHD), multi-viewpoint 3D video, and hologrambroadcasting.

However, it may not be efficient for an MPEG-2 TS with a packet with afixed length of 188 bytes to transport contents with higher resolutionthan those of a typical HDTV by using the IP network.

SUMMARY

Embodiments provide methods and apparatuses capable of efficientlytransmitting/receiving media transport streams such as an MPEG-2 TS inan IP based transport system.

Embodiments also provide a method and apparatus capable of efficientlystoring a media transport stream such as an MPEG-2 TS.

In one embodiment, A method of transmitting media transport streams byusing an IP based transport system includes removing some data frommedia transport streams to be transmitted; forming at least one entrybox including information for reinserting the removed data into themedia transport streams; forming a media data (mdat) box including themedia transport streams from which the data has been removed; andpositioning and transporting a compression information box including theat least one entry box before the mdat box.

In another embodiment, a method of receiving media transport streams byusing an IP based transport system, the method includes sequentiallyreceiving a compression information box that includes at least one entrybox and an mdat box that includes media transport streams from whichsome data are removed; acquiring information for reinserting the removeddata from the entry box; and reinserting the removed data into the mediatransport streams that is included in the mdat box, by using theacquired information.

In further another embodiment, an apparatus for transmitting mediatransport streams by using an IP based transport system includes acontrol unit removing some data from media transport streams to betransmitted and forming a compression information box that includes atleast one entry box and a media data (mdat) box that includes mediatransport streams from which the data is removed; and a networkinterface unit positioning and transporting the compression informationbox before the mdat box, and wherein the entry box includes informationfor reinserting the removed data into the media transport streams.

In still further another embodiment, an apparatus for receiving mediatransport streams by using an IP based transport system includes anetwork interface unit sequentially receiving a compression informationbox that includes at least one entry box and a media data (mdat) boxthat includes media transport streams from which some data is removed;and a control unit acquiring information for reinserting the removeddata, from the entry box and reinserting the removed data into mediatransport streams included in the mdat box, by using the acquiredinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view representing a configuration of an IP based mediatransmitting/receiving system according to an embodiment of the presentinvention.

FIG. 2 is a block diagram representing a configuration of a transmittingapparatus according to an embodiment of the present invention.

FIG. 3 is a flow chart representing a media transmitting methodaccording to an embodiment of the present invention.

FIG. 4 is a view representing an embodiment of a configuration of amedia transport stream.

FIG. 5 is a view representing a media data format according to anembodiment of the present invention.

FIG. 6 is a view representing the definition of a compressioninformation (cinf) box illustrated in FIG. 5.

FIG. 7 is syntax representing an embodiment of a configuration of thecompression information (cinf) box.

FIG. 8 is a view representing the definition of the compression entrybox (comb) illustrated in FIG. 5.

FIG. 9 is syntax representing an embodiment of a configuration of thecompression entry box (comb).

FIG. 10 is a view representing the definition of the num packet signalbox (npsb) illustrated in FIG. 5.

FIG. 11 is syntax representing an embodiment of a configuration of thecompression information and null packet signal box (npsb).

FIG. 12 is a view representing an embodiment of a method of forming amedia data format.

FIG. 13 is a view representing an embodiment of a configuration of amedia data stream transmitted from a transmitting apparatus.

FIG. 14 is a block diagram representing a configuration of a receivingapparatus according to an embodiment of the present invention.

FIG. 15 is a flow chart representing a method of receiving mediaaccording to an embodiment of the present invention.

FIG. 16 illustrates an embodiment of a method of reinserting data into areceived media stream as a flow chart.

FIG. 17 is a graph for explaining an effect of a mediatransmitting/receiving system according to an embodiment of the presentinvention.

FIG. 18 is a block diagram representing a first embodiment of aconfiguration of an IPTV receiver according to the present invention.

FIG. 19 is a block diagram representing a second embodiment of aconfiguration of an IPTV receiver according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Methods of transmitting/receiving media and transmitting/receivingapparatuses using these methods according to embodiments will bedescribed in detail below with reference to FIGS. 1 to 19.

Detailed descriptions related to well-known functions or configurationswill be ruled out in order not to unnecessarily obscure subject mattersof the present invention. The terms described below are those defined byconsidering the functions in embodiments of the present invention andmay vary depending on the intention or of a user or an operator orpractice. Therefore, the definitions will be made on the basis of thecontents throughout the specification.

FIG. 1 illustrates a configuration of an IP based mediatransmitting/receiving system according to an embodiment of the presentinvention as a block diagram, and the illustrated transmitting/receivingsystem may include a transmitting apparatus 100 and a receivingapparatus 200.

Referring to FIG. 1, the transmitting apparatus 100 and receivingapparatus 200 transmits/receives data by using an internet protocol (IP)based transport system, and the data may be streamed by using forexample, transmission control protocol (TCP) and hypertext transferprotocol (HTTP) through a web server.

The transmitting apparatus 100 may receive, convert, and transportcontents from a content provider or may store and keep them in a mediadatabase.

For example, the media transport stream provided from the contentprovider may be one according to MPEG-2 standard, namely, an MPEG-2transport stream (MPEG-2 TS) that is widely employed in variousapplications. The receiving device 100 may convert the MPEG-2 TS into aformat suitable for IP based delivery and transport it through a networksuch as internet or may store it in the media DB.

Meanwhile, the receiving apparatus 200 may receive the media transportstream from the transmitting apparatus 100 by using the IP basedtransport system, convert the received media transport stream, and thenreplay or store it in a local storage.

For example, the receiving apparatus 200 may convert and process themedia transport stream received from the transmitting apparatus 100 intoan MPEG-2 TS format, and replay or store it into the local storage.

The MPEG-2 TS is targeted at lossy storage and transport systems such asdigital video broadcasting environments including digital videobroadcasting (DVB) or advanced television system committee (ATSC). TheMPEG-2 TS based media is widely used and its encoding and decodingengines are being usefully used in digital video broadcastingenvironments.

Meanwhile, a media encapsulation format such as the MPEG-2 TS may alsobe used for other systems that use IP based transport, and may includehybrid deployment of components over the internet and components inlocal broadcasting environments in which services may be providedthrough multiple connections.

As the MPEG-2 TS in the encapsulation format is widely used and the IPbased transport system is widely used as described above, their hybriduse may be very effective. For example, the media transport stream inthe MPEG-2 TS format may be streamed by using HTTP.

However, the type and properties of a transport mechanism for IP basednew target applications are very different from those of targettransport mechanisms in the MPEG-2 TS standard, and thus newcompatibility and optimization matters may occur.

According to an embodiment of the present invention, if being used in atarget system such as the IP based transport system (for example, HTTPbased streaming), a media transport efficiency may be enhanced byremoving the redundancy of MPEG-2 TS based media.

To that end, the transmitting apparatus 100 may prepare contents forHTTP streaming by performing segmentation and compression for removingthe redundancy on the MPEG-2 TS based media.

Meanwhile, the compressed data may be stored in the storage of thetransmitting apparatus 100 or be transmitted to the receiving apparatus200 through the HTTP based transport system.

In addition, the receiving apparatus 200 may decompress and recombinethe segments transported through the HTTP streaming to restore theMPEG-2 TS.

FIG. 2 illustrates a configuration of a transmitting apparatus accordingto an embodiment of the present invention as a block diagram, and theillustrated transmitting apparatus 100 may include a control unit 110, anetwork interface unit 120, and a storing unit 130.

Referring to FIG. 2, the control unit 110 may remove some data frominput MPEG-2 media transport streams and create information on theremoved data.

The MPEG-2 TS is defined to use for lossy systems and has a fixed packetsize of 188 bytes to satisfy the requirements of an asynchronoustransfer mode (ATM) network. Its timing and buffering model mainly focuson a channel at a fixed bit rate.

On the other hand, an IP based transport system according to anembodiment of the present invention may use reliable transport protocolwith variable bandwidth conditions, such as an HTTP based streamingapplication.

In the HTTP based streaming application, media data such as MPEG-2 TSmay be transported by using HTTP/TCP in the type of segments or segmentbyte ranges.

Meanwhile, if the receiving apparatus 200 working as a client wants tostart randomly replaying a media sample, a first proper segment or byterange may be fetched by using HTTP streaming protocol.

Subsequently, the sample may be positioned and the timing of the samplemay be restored to replay the samples contiguous to a target sample. Inaddition, if there is a need for continuous replay, new continuoussegments may be fetched simultaneously with decoding.

In terms of technology, a transport streaming format such as the MPEG-2TS may not be suitable for the reliable and various bit rate mechanismsof the HTTP based transport as described above.

According to an embodiment of the present invention, in the IP basedtransport system (for example, HTTP streaming), the transmittingapparatus 110 may remove unnecessary redundancy data from transportstreams to be transmitted in order to decrease unnecessary overheadpresent in a transport stream such as an MPEG-2 TS.

For example, the unnecessary data removed from the MPEG-2 TS issyntax-based redundancy and may be a specific syntax element included inthe header of MPEG-2 TS, a stuffing byte, or a null packet.

Meanwhile, the transmitting apparatus 100 may form information on thedata removed from the MPEG-2 TS described above as at least one box, andthe box may have a form according to an ISO/IEC 14496-12 ISO base mediafile format.

For example, the control unit 110 of the transmitting apparatus 100configures a compression information box including at least one entrybox, and the entry box may include information for reinserting the dataremoved from the MEGP-2 TS into the MPEG2-2 TS at the receivingapparatus 200.

In addition, the control unit 110 may configure a media data (mdat) boxincluding the MPEG-2 TS from which the data has been removed.

Meanwhile, media data may be transmitted through the network interfaceunit 120, the media data including a compression information boxincluding information for reinserting the removed data and an mdat boxincluding the MPEG-2 TS from which the data has been removed.

In this case, the MPEG-2 TS from which the data has been removed may beincluded in the mdat box segment by segment, and the compressioninformation box may be positioned before the mdat box and transported tothe receiving apparatus 200 through an IP based transport system.

Embodiments of a method of transmitting media according to the presentinvention will be described in more detail below with reference to FIGS.3 to 13.

FIG. 3 illustrates a method of transmitting media according to anembodiment of the present invention as a flow chart, and the illustratedtransmitting method will be described in connection with a block diagramrepresenting a configuration of a transmitting apparatus according to anembodiment of the present invention illustrated in FIG. 2.

Referring to FIG. 3, the control unit 110 of the transmitting apparatus100 removes some data from a media transport stream to be transmitted instep 5300.

For example, the control unit 110 may remove unnecessary redundancy datafrom input MPEG-2 TS.

Referring to a configuration of the MPEG-2 TS illustrated in FIG. 4, atransport packet includes 4-byte header and 184-byte payload followingthe header and thus has a size of 188 bytes regardless of intendedtransport mechanisms.

Meanwhile, the header may include an 8-bit sync byte, an 1-bit transporterror indicator, an 1-bit payload unit start indicator, an 1-bittransport packet priority, a 13-bit packet identification (PID), 2-bittransport scrambling control, 2-bit adaptation field control (AFC), anda 4-bit continuity counter.

The size of the packet is considerably smaller than those of data unitstransported from the general use scenario of HTTP streaming and thisoccurs considerable redundancy together with the fact that severalsyntax elements in the header described above focus on transportingthrough the lossy system of an MPEG-2 TS.

For example, the syntax elements of the header, such as the sync byte,transport error indicator, and continuity counter may be unnecessarydata in an IP based transport system such as HTTP streaming.

More particularly, at a high packetization rate of 188 bytes per packet,one unnecessary byte such as the sync byte may occur unnecessaryoverhead of above approximately 0.5%.

Meanwhile, by the packetization mechanism of an MPEG-2 TS with a fixedsize of 188 bytes per packet described above, byte stuffing may be used.

For example, if a program specific information (PSI) transport streampacket is partially filled or a program elementary stream packetpartially fills a TS packet, the unnecessary stuffing bytes describedabove may be included in the MPEG-2 TS.

That is, in order to satisfy a fixed bit rate of 188 bytes per packet,bytes with a value of 0xFF may be repetitively inserted into the payloadof the MPEG-2 TS, and the stuffing byte may thus occur redundancy inHTTP streaming.

In addition, in order to achieve a fixed bandwidth or a desiredmultiplexing ratio, unnecessary null packets may be inserted into theMPEG-2 TS. In this case, a decoder removes null packets as describedabove and then performs decoding.

For example, if the PID included in the header is 0x1FFF, it mayrepresent that a corresponding packet is a null packet, and the payloadof the null packet may be entirely filled with 0 or 0xFF bytes.

According to an embodiment of the present invention, the control unit110 of the transmitting apparatus 100 may remove unnecessary datadescribed above, such as the sync byte of header, stuffing bytes or nullpackets, from the MPEG-2 TS and thus remove syntax based redundancy.

However, the specific syntax elements included in the header of theMPEG-2 TS, stuffing bytes, and null packets are just examples of anembodiment of the present invention. The present invention is notlimited thereto but the transmitting apparatus 100 may remove dataunnecessary for an IP based transport system from the MPEG-2 TS, besidesthe data described above.

For example, subtitle tracks including considerable redundancy orseveral types of payload data such as an electronic program guide may bedirectly multiplexed into the transport stream, and the sub-optimalcompression of video and audio data may also contribute to addingredundancy.

Subsequently, the control unit 110 forms at least one entry boxincluding information necessary for reinserting the removed data intothe media transport stream in step S310.

For example, the control unit 110 may configure information as an entrybox, the information signaling so that the receiving apparatus 200working as a client may reinsert the data removed in step S300 into thetransport stream. The entry box may be included in a compressioninformation box.

In step S320, the control unit 110 forms an mdat box including a mediatransport stream from which the data has been removed. The networkinterface unit 120 positions and transports the compression informationbox including at least one entry box before the mdat box in step S330.

For example, the control unit 110 may encapsulate the MPEG-2 TS fromwhich unnecessary data has been removed in step S300, into an mdat boxaccording to an ISO/IEC 14496-12 ISO base media file format.

FIG. 5 illustrates an embodiment of a configuration of a media dataformat according to an embodiment of the present invention.

Referring to FIG. 5, media data 500 includes a compression information(cinf) box and an mdat box, and the compression information (cinf) boxmay include one or more compression entry boxes (combs) that includeinformation for reinserting the data removed from the transport stream.

In addition, an MPEG-2 TS from which the unnecessary data describedabove, such as the sync byte of header, stuffing bytes or null packetshas been removed may be included in the mdat box segment by segment.

Meanwhile, as illustrated in FIG. 5, the compression information (cinf)box may further a null packet signal box (npsb) that provides signalingfor reinserting the removed null packet.

Signaling a client side, namely the receiving apparatus 200 forreinserting the removed data as described above may be carried out bybox data types illustrated in FIGS. 6 to 11, and a remainder operatorsymbolized as ‘%’ may be used in syntax.

Referring to FIGS. 6 and 7, the compression information (cinf) box mayinclude one or more compression entries, each of which may includeinformation necessary for reinserting the data removed from the MPEG-2TS into the receiving apparatus 100.

Referring to FIG. 8, the compression entry box (comb) may provideinformation that signals the receiving apparatus 200 a method ofreinserting the removed data into the correct position of media data torestore original data at a syntax level.

Meanwhile, the compression entry box (comb) is included in thecompression information (cinf) box as illustrated in FIGS. 6 and 7, andone or more compression entry boxes may be present in the compressioninformation (cinf) box.

FIG. 9 is syntax representing an embodiment of a configuration of thecompression entry box (comb).

Referring to FIG. 9, the version is an integer representing the versionof a corresponding box and may have a value of ‘0’ or ‘1’.

Meanwhile, flags are 24-bit integers with flags and may be defined asthe following values.

‘sync-byte-removed’ represents that the sync byte of a header that is asyntax element of an MPEG-2 TS has been removed, and its flag value mayhave ‘0x000001’.

Meanwhile, the sync-byte-removed has the same value in all thecompression entry boxes (comb) that have been included in onecompression information (cinf) box.

‘reinsert_data’ represents repeated data, namely a string to bereinserted at the receiving apparatus 200, and ‘string_length’represents may represent how many times the reinsert_data is repeated toreinsert the string.

Meanwhile, the reinsert_data may be designated in the following repeatedloop so that each entry has different value.

‘diff_offset’ provides information on a position into which the repeatedbyte string will be reinserted and to that end, may represent thedifferential byte offset of the position to be reinserted.

For example, the diff_offset may represent the differential byte offsetfrom the last byte of a previously inserted string to the inserted bytestring.

Meanwhile, in the case of the byte string reinserted for the first time,the diff_offset may represent the offset from the first byte ofcorresponding media data to a corresponding byte string.

‘eight-bit-offset’ represents that the diff_byte is expressed as an8-bit data type, and may have a flag value of 0x000002.

In addition, ‘sixteen-bit-offset’ represents that the diff_byte isexpressed as a 16-bit data type, and may have a flag value of 0x000004.

Meanwhile, ‘entry_count’ may represent the umber of entries that arepresent in the following loop.

If a byte such as a stuffing byte that is repeated with a specific valueis removed, the compression entry box (comb) as described above withreference to FIGS. 8 and 9 may provide information for reinserting theremoved byte.

Referring to FIG. 10, the null packet signal box (npsb) may provideinformation for signaling the receiving apparatus 200 working as aclient a method of reinserting the removed null packet into the correctposition of media data and restoring original data at a syntax level.

Meanwhile, the null packet signal box (npsb) is included in thecompression information (cinf) box illustrated in FIGS. 6 and 7, and onenull packet signal box may be present in the compression information(cinf) box.

FIG. 11 is syntax representing an embodiment of a configuration of thenull packet signal box (npsb).

Referring to FIG. 11, a version is an integer representing the versionof a corresponding box and may have a value of ‘0’ or ‘1’.

Meanwhile, flags are 24-bit integers with flags and may be defined asthe following values.

‘packet_offset’ may represent the offset of the first transport stream(TS) packet from the start of an associated media entity.

In addition, ‘packet offset flag’ represents whether the packet_offsetis present, and its flag value may be 0x000001.

‘null_packet’ represents whether a corresponding transport packet is anull packet. If its field value is ‘0’, the transport packet is not anull packet, and if its field value is ‘1’, the transport packet is anull packet.

For example, the null packet signal box (npsb) includes a plurality ofentries that correspond to each of a plurality of transport packets inan MPEG-2 TS to be restored, and the plurality of entries each mayinclude the null_packet field that represents whether a transport packetcorresponding to a corresponding entry is a null packet.

If the value of the null_packet field is ‘0’, there is no need for thereceiving apparatus 200, a client side to perform an operation ofreinserting a null packet because a corresponding media packet is not anull packet in media.

On the other hand, if the value of the null_packet field is ‘1’, thereceiving apparatus 200, a client side may insert a null packet to thecorresponding position of received data to restore an MPEG-2 TS becausea corresponding media packet is a null packet in the media.

Meanwhile, ‘entry_count’ may represent the number of entries that arepresent in the following loop.

A media data format according to an embodiment of the present inventionas described above with reference to FIGS. 5 to 11 may be used fortransporting media transport streams to the receiving apparatus 200through the network interface unit 120.

In this case, the transmitting apparatus 100 may transport media datathat includes an mdat box including an MPEG-2 TS from which unnecessarydata has been removed and a compression information (cinf) box includinginformation for reinserting the removed data, to the receiving apparatus200 by using an IP based transport system to decrease the bit rate of amedia transport stream and simultaneously increase compatibility with anISO base media file format.

According to another embodiment of the present invention, the MPEG-2 TSconverted into a media data format as described with reference to FIGS.5 to 11 may be stored in the storing unit 130 of the transmittingapparatus 100, and a smaller space for store a media file may thus beconsumed.

Meanwhile, the media data stored in the storing unit 130 may then betransported through the network interface unit 120.

FIG. 12 illustrates an embodiment of a method of configuring a mediadata format and represents a method of configuring media data with aformat as described with reference to FIGS. 5 to 11.

Referring to FIG. 12, MPEG-2 TS packets each have a fixed bit rate of188 bytes, and may be transported segment by segment, including one ormore packets (for example, three MPEG-2 TS packets)

Since a third packet 603 of the MPEG-2 TS packets illustrated in FIG.12A that has been included in a first segment is a null packet, thetransmitting apparatus 100 may remove the third packet 603 from theMPET-2 TS as illustrated in FIG. 12B.

In addition, since a fourth packet 604 included in a second segmentincludes stuffing bytes and a sixth packet 606 includes a sync byte, thetransmitting apparatus 100 may remove the stuffing bytes from the fourthpacket 604 of the MPE-2 TS and the sync byte from the sixth packet 606as illustrated in FIG. 12B.

Meanwhile, since a seventh packet 607 and an eighth packet 608 that areincluded in a third segment are null packets, the transmitting apparatus100 may remove the seventh packet 607 and eighth packet 608 from theMPEG-2 TS as illustrated in FIG. 12B.

In addition, since a tenth packet 610 included in a fourth segmentincludes stuffing bytes, the transmitting apparatus 100 may remove thestuffing bytes from the tenth packet 610 of the MPEG-2 TS as illustratedin FIG. 12B.

Meanwhile, each of the MEGP-2 TSs from which the unnecessary data hasbeen removed may be included in an mdat box segment by segment.

As illustrated in FIG. 12C, the transmitting apparatus 100 may configurecompression information (cinf) boxes by using information forreinserting the removed data as described above, and the compressioninformation (cinf) box may include one or more compression entry boxes(combs) and null packet signal boxes (npsbs).

In the case illustrated in FIG. 12, a first compression information(cinf) box may include information representing that the third packet603 is a null packet, and the null_packet of an entry corresponding tothe third packet 603 of entries of the null packet signal box (npsb)that has been included in the first compression information (cinf) boxmay have a field value of ‘1’, for example.

In addition, a second compression information (cinf) box may provideinformation representing that the fourth packet 604 includes stuffingbytes and the sixth packet 606 includes a sync byte.

For example, the compression entry box (comb) included in the secondcompression information (cinf) box may include the differential byteoffset of the position of stuffing bytes present in the fourth packet604, namely the offset value (diff_offset 1) from the first byte ofmedia to the stuffing bytes, as diff_offset.

In addition, sync_byte_removed have a value of 0x000001 to representthat the compression entry box (comb) included in the second compressioninformation (cinf) box includes a sync byte.

In this case, the sync_byte_removed in all the compression entry boxes(combs) included in the second compression information (cinf) box has aflag value of 0x000001.

Meanwhile, a third compression information (cinf) box may provideinformation representing that the seventh packet 607 and eighth packet608 are null packets and to that end, the null_packet of each of entriescorresponding to the seventh packet 607 and eighth packet 608 of entriesof the null packet signal box (npsb) that has been included in the thirdcompression information (cinf) box may have a field value of ‘1’.

In addition, a fourth compression information (cinf) box may provideinformation representing that the tenth packet 610 includes stuffingbytes and to that end, the compression entry box (comb) included in thefourth compression information (cinf) box may include the differentialbyte offset value diff_offset 2 of the position of a stuffing bytepresent in the tenth packet 610.

In this case, the differential byte offset value diff_offset 2 maycorrespond to the offset value from the last byte of previously insertedstuffing bytes to a corresponding stuffing byte as illustrated in FIG.12A.

Then, as illustrated in FIG. 12D, the transmitting apparatus 100 mayconfigure a media data format in which the configured compressioninformation (cinf) boxes are respectively attached and transported tothe front of corresponding mdat boxes.

FIG. 13 illustrates an embodiment of a configuration of a media datastream transported from a transmitting apparatus.

Referring to FIG. 13, compression information for an

MPEG-2 TS file segment, namely information for reinserting the dataremoved from the MPEG-2 TS file segment may be attached to the front ofa corresponding segment.

For example, if the compression information is attached in a binaryformat, the MPEG-2 TS data from which unnecessary data has been removedas described above may be encapsulated into an mdat box segment bysegment or by byte range for easy access and division.

As illustrated in FIG. 13, a media data stream 500 may start with asegment type (styp) box, a compression information (cinf) box and one ormore compression entry boxes (combs) included therein may be added tothe start portion, and then a null packet signal box (npsb) may bepresent.

The segment type (styp) box may have the same syntax structure as a filetype (ftyp) box defined in an ISO/IEC 14496-12 ISO base media fileformat, except that its box type is set as ‘styp’, it has a brand of‘etsf’, and its minor version is set to ‘1’.

Meanwhile, the order of the compression entry boxes (combs) may play animportant role in processing the receiving apparatus 200, a client side.

By the operation of the receiving apparatus 200 as described above, anull packet may be simplified to approximately 7-bit compressedinformation, and after removing a sync byte, it may need to transportonly one next byte.

The size of the smallest string in a segment removed at a server side,namely transmitting apparatus 100 may depend on the smallest availablesize of a data type used to express the diff_offset of the compressionentry box (comb) as described above.

For example, according to a test result, all signaling for thediff_offset may be performed in 16-bit data types.

Thus, there may be approximately 3-byte overhead to remove a string ofrepeated data and the transmitting apparatus 100, a server side mayremove any string that is a size of 3 or bigger.

In this case, removing a string of the size of 3 just keeps thediff_offset small and may not assist directly in compression.

Embodiments of a method and apparatus for receiving media according tothe present invention will be described in detail below with referenceto FIGS. 14 to 16.

The receiving apparatus 200 according to an embodiment of the presentinvention may receive compression information for reinserting a mediatransport stream from which some data has been removed and the removeddata from the transmitting apparatus 100 and may reinsert the removeddata into the received media transport stream by using the compressioninformation.

FIG. 14 illustrates a configuration of a receiving apparatus accordingto an embodiment of the present invention as a block diagram, and theillustrated receiving apparatus 200 may include a network interface unit210, a control unit 220, and a storing unit 230.

Referring to FIG. 14, the network interface unit 210 may receive atransport stream with a data format as described above with reference toFIGS. 3 to 13 from the transmitting apparatus 100 through an IP basedtransport system.

For example, the network interface unit 210 may sequentially receive acompression information (cinf) box including at least one compressionentry box (comb) and an mdat box including an MPEG-2 TS segment bysegment from which some data has been removed, and the compressioninformation (cinf) box may selectively include a null packet signal box(npsb).

The control unit 220 may acquire information for reinserting the removeddata, from the compression information (cinf) box (or null packet signalbox (npsb)) and reinsert the removed data into the MPEG-2 TS included inthe mdat box by using the acquired information.

Meanwhile, the media transport stream received through the networkinterface unit 210 may be stored in the storing unit 130, and the storedmedia transport stream may then be output to the MPEG-2 TS after theremoved data is reinserted through the control unit 220.

FIG. 15 illustrates a method of receiving media according to anembodiment of the present invention as a flow chart, and the illustratedreceiving method will be described in connection with a blocking diagramthat represents a configuration of a receiving apparatus according to anembodiment of the present invention illustrated in FIG. 14.

Referring to FIG. 15, the network interface unit 210 of the receivingapparatus 200 receives a compression information box including at leastone entry box in step S700 and then receives an mdat box including amedia transport stream from which some data has been removed, in stepS710.

Since configurations of the received compression information (cinf) boxand mdat box may be the same as those described with reference to FIGS.3 to 13, their details descriptions will not be repeated.

Then, the control unit 330 acquires information for reinserting theremoved data, from the entry box in step S720, and reinserts the removeddata into the media transport stream included in the mdat box, by usingthe acquired information in step S730.

An embodiment of a method of reinserting data into the received mediatransport stream at the receiving apparatus 200 will be described indetail below with reference to FIG. 16.

Referring to FIG. 16, the control unit 220 reinserts the removed datainto a corresponding position at the transmitting apparatus 100, byusing a first compression entry box (comb) included in the compressioninformation (cinf) box in steps S800 and S810.

For example, if repeated bytes such as stuffing bytes have been removedfrom an MPEG-2 TS included in an mdat box, the control unit 220 mayidentify the removed data, the position of the removed bytes and thenumber of times repeated by using reinset_data, diff_offset, andstring_length included in the first compression entry box (comb).

Meanwhile, the control unit 220 may reinsert the removed bytes into theMPEG-2 TS included in the mdat box, according to the informationidentified by using the first compression entry box (comb).

The control unit 220 may successively perform the operation in step S810described above for each of N compression entry boxes (combs) includedin the compression information (cinf) box in steps S800 to S830 toreinsert all the bytes removed at the transmitting apparatus 100, suchas stuffing bytes into the MPEG-2 TS included in the mdat box

In addition, while steps S800 to S830 are performed, the control unit220 may identify a flag sync_byte_removed at N compression entry boxes(combs) included in the compression information (cinf) box.

Meanwhile, all the compression entry boxes (combs) included in onecompression information (cinf) box may have the same flag value.

Then, a sync byte is reinserted on the basis of a flag sync_byte_removedidentified at the N compression entry boxes (combs) in step S840.

For example, if the sync_byte_removed in the N compression entry boxes(comb) included in the compression information (cinf) box has a flag of0x000001, it is considered that a sync byte has been removed from acorresponding segment and the control unit 220 may thus reinsert theremoved sync byte into the correct position of the MPEG-2 TS included inthe mdat box.

After steps S800 to S840 have been performed, the control unit 220reinserts a null packet according to the value of null_packet fielddesignated by a null packet signal box (npsb) in step S850.

For example, if the value of the null_pcaket field of a specific one ofentries included in the null packet signal box (npsb) is set to ‘1’, thecontrol unit 220 may identify that a packet corresponding to thespecific entry is a null packet and may then reinsert the null packetinto the position of the corresponding packet of the MPEG-2 TS includedin the mdat box.

FIG. 17 illustrates a result of testing an effect of a mediatransmitting/receiving system according to an embodiment of the presentinvention, as a graph.

The test has been conducted on the following four exemplary contents.

1. Munich Channel 23 (capture internally, to be published). It iscaptured DVB transmission, duration approx. 3 minutes 10 seconds.

2. Content from RTV Slovenija, duration approx. 2 minutes 6 seconds.

3. Content from WMPT-DT (PBS Annapolis Md.), duration approx. 5 seconds.

4. Elephant Dream, segment 1.

Referring to FIG. 17, a decrease rate in data size due to compressionmay decrease in the order of removing null packets, stuffing bytes, andsync bytes.

The methods of receiving and processing IP based media as described withreference to FIGS. 1 to 17 may be performed by an IPTV receiveraccording to an embodiment of the present invention.

To that end, the IPTV receiver may receive the media transmitted from atransmitting side (for example, a media server) and may have aconfiguration as described with reference to FIGS. 5 to 13.

In addition, the IPTV receiver may reinsert the removed data to themedia transport stream received from the transmitting side to replay orstore it in an inner storage and the replayed or stored media may have aconfiguration such as an MPEG-2 TS format.

Meanwhile, the IPTV receiver may perform the media receiving method asdescribed with reference to FIGS. 14 to 16.

A configuration of an IPTV receiver according to an embodiment of thepresent invention will be described in more detail below with referenceto FIGS. 18 and 19.

FIG. 18 illustrates a configuration of an IPTV receiver according to anembodiment of the present invention, as a block diagram.

The IPTV receiver according to the embodiment of the present inventionmay include a separate tuner to be able to receive terrestrialbroadcasting, cable broadcasting, satellite broadcasting, etc. For theconvenience of description, the present invention describes on the basisof a configuration that receives IPTV services provided by an IPnetwork.

Meanwhile, the acronym ITF indicates an open IPTV terminal function andmay mean a receiver that includes functional modules required forsupporting IPTV services.

The IPTV receiver may include a network interface unit 901, a TCP/IPmanager 902, a service delivery manager 904, a PVR manager 905, ade-multiplexer 908, a data decoder 907, an audio/video decoder 912, anA/V display & OSD module 915, application manager 913 and 914, a serviceinformation (SI) metadata DB 911, a service discovery manager 909, aservice control manager 903, a metadata manager 910, and a content DB906.

Referring to FIG. 18, the network interface unit 901 receives andtransports packets from/to a network. That is, the network interfaceunit 901 receives services and media contents from service providersthrough the network.

The TCP/IP manager 902 participates in delivering packets from sourcesto destinations that are received and transported by the IPTV receiver.In addition, the TCP/IP manager 902 classifies the received packetsaccording to protocols and outputs the classified packets to the servicedelivery manager 904, service discovery manager 909, service controlmanager 903, and metadata manager 910.

The service delivery manager 904 is responsible for controlling thereceived service data. For example, if controlling real-time streamingdata, RTP/RTCP may be used.

If the real-time streaming data is transported by using RTP, the servicedelivery manager 904 parses the received data packets according to RTPto transport them to the de-multiplexer 908 or store them in the contentDB 906 according to the control of the service manager 914. In addition,the service delivery manager 904 feeds the information received from thenetwork back to a service providing server side, by using RTCP.

The de-multiplexer 908 de-multiplexes the received packets to audio,video, program specific information (PSI) data, etc. and transports themto the audio/video decoder 912 and data decoder 907, respectively.

The data decoder 907 decodes service information, for example programspecific information (PSI). That is, the data decoder 907 receives anddecodes a de-multiplexed PSI section, program and service informationprotocol (PSIP) section, or DVB-service information (SI) section fromthe de-multiplexer 908.

In addition, the data decoder 907 decodes the received sections, andcreates and stores a database on service information in the serviceinformation DB 911.

The audio/video decoder 912 decodes the video data and audio datareceived from the de-multiplexer 908. The audio and video data decodedfrom the audio/video decoder 912 is provided to users through the A/Vdisplay and OSD module 915.

The application manager manages the general conditions of the IPTVreceiver, provides a user interface and manages the other managers. Tothat end, the application manager includes a user interface manager 913and a service manager 914.

The user interface manager 913 provides a graphic user interface (GUI)for users by using an on screen display (OSD) and receives key inputfrom users to perform the operations of the receiver according to theinput. For example, if key input related to channel selection isreceived from users, the key input signal is transported to the servicemanager 914.

The service manager 914 controls managers associated with services, suchas the service delivery manager 904, service discovery manager 909,service control manager 903, and metadata manager 910.

In addition, the service manager 914 creates a channel map and selects achannel by using the channel map according to the key input receivedfrom the user interface manager 913. In addition, the service manager914 receives the service information of channels from the data decoder907 and sets the audio/video packet identifier of the selected channelfor the de-multiplexer 908.

The service discovery manager 909 provides information required forselecting a service provider that provides services. If a signal forchannel selection is received from the service manager 914, the servicediscovery manager 909 searches for services by using the information.

The service control manager 903 is responsible for selecting andcontrolling services. For example, if a user selects a live broadcastingservice such as a typical broadcasting technique, the service controlmanager 903 may select and control services by using IGMP or RTSP. If auser selects a video on demand (VOD) service, the service controlmanager may select and control services by using RTSP.

The RTSP protocol may provide a trick mode for real-time streaming. Inaddition, the service control manager 903 may initialize and managesessions through an IMC gateway by using IP multimedia subsystem (IMS)and session initiation protocol (SIP). The protocols are examples andthe other protocols may be used according to implementations.

The metadata manager 910 manages the metadata associated with servicesand stores the metadata in the service information DB 911.

The service information DB 911 stores service information that the datadecoder 907 has decoded, metadata that the metadata manager 910 manages,and information that the service discovery manager 909 provides and isrequired for selecting a service provider. In addition, the serviceinformation DB 911 may store setup data on systems.

The service information DB 911 and content DB 906 each may beimplemented by using a non-volatile RAM (NVRAM) or a flash memory andmay be implemented as two logically divided regions on the same storingregion.

The PVR manager 905 is a module for recording and replaying livestreaming contents and may collect metadata on the recorded contents andcreate additional information to be provided to users, such as thumbnailimages or an index.

The functions of the control unit of the IPTV receiver according to anembodiment of the present invention may be divided and implemented intoa plurality of modules, such as the TCP/IP manager 902, service deliverymanager 904, PVR manager 905, application manager 913 and 914, servicediscovery manager 909, service control manager 903, and metadata manager910.

For example, the TCP/IP manager 902 may filter SD&S information by usingtarget package information as described above and control so that thenetwork interface unit 901 requests a server only payload or a segmentcorresponding to a specific package (for example, a package that theIPTV receiver has joined) and receives it.

Alternatively, the TCP/IP manager 902 may filter the SD&S informationreceived in a multicast scheme by using the target package informationso that only payload or a segment corresponding to a specific package isparsed and processed by the data decoder 907.

FIG. 19 illustrates another embodiment of a configuration of an IPTVreceiver according to the present invention as a block diagram andrepresents the functions of the IPTV receiver as functional blocks. Thesolid arrows illustrated in FIG. 19 correspond to data paths and thedotted arrows correspond to control signal paths.

Cable modem, DSL modem, etc. 1001 are interfaces for enabling ITF to beconnected to the IP network and demodulate the signals transportedthrough physical mediums to restore digital signals.

Ethernet NIC 1002 restores the signals received through the physicalinterface to IP data, and IP network stack 1007 processes each layeraccording to IP protocol stack.

Meanwhile, an XML parser 1009 parses XML documents among received IPdata, and a file handler 1008 processes the data transported in a filetype through FLUTE among the received IP data.

An SI handler 1011 processes a part corresponding to IPTV serviceinformation among the received file-type data and stores it in storage1012, and an EPG handler 1010 may process a part corresponding to IPTVEPG information among the received file-type data and store it in thestorage 1012.

The storage 1012 stores various data such as SI and EPG.

An SI decoder 1013 receives and analyzes SI data from the storage 1012and acquires channel map information. An EPG decoder 1014 analyzes theEPG data stored in the storage 1012 and stores information required forconfiguring EPG.

An ITF operation controller 1015 is a main controller that controls theoperations of the ITF, such as channel change or EPG display.

A channel service manager 1016 may perform operations, such as channelchange according to user input and an application manager 1017 mayperform application services, such as EPG display according to userinput.

An MPEG-2 de-multiplexer 1003 may extract MPEG-2 transport stream datafrom received IP datagram and transport it to a corresponding moduleaccording to a packet identifier (PID).

In addition, an MPEG-2 PSI/PSIP parser 1004 may extract and parsePSI/PSIP data including the packet identifier of A/V data and connectioninformation on a program element from the MPEG-2 transport stream.

Meanwhile, an A/V decoder 1005 decodes and delivers input audio andvideo data to a display module 1006, and the display module 1006 mayoutput the decoded A/V data or application.

While methods and apparatuses for transmitting/receiving media accordingto embodiments have been described where a media transport streamtransmitted/received between the transmitting apparatus 100 andreceiving apparatus 200 is MPEG-2 TS, the present invention is notlimited thereto but may be applied to various transport stream formatsother than the MPEG-2 TS.

According to an embodiment of the present invention, intransmitting/receiving media transport streams such as MPEG-2 TS byusing an IP based transport system, a media transport stream from whichunnecessary data has been removed and information for reinserting theremoved data are formed according to an ISO/IEC 14496-12 ISO base mediafile format and the bit rate of the media transport stream may thus bedecreased and at the same, the compatibility with an ISO base media fileformat may be increased.

In addition, according to another embodiment, a media transport streamfrom which unnecessary data has been removed and information forreinserting the removed data are formed according to an ISO base mediafile format and stored in a media file and a smaller space for storingthe media file may thus be consumed.

The media transmitting/receiving methods described above may bemanufactured as a program for being executed on a computer and stored ina computer readable recording medium, and examples of the computerreadable recording medium include read-only memory (ROM), random-accessmemory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical datastorage devices, and carrier waves (such as data transmission throughthe Internet).

The computer readable recording medium can also be distributed overnetwork coupled computer systems so that the computer readable code isstored and executed in a distributed fashion. (Also, functionalprograms, codes, and code segments for accomplishing the presentinvention can be easily construed by programmers skilled in the art towhich the present invention pertains.)

In addition, although exemplary embodiments have been illustrated anddescribed above, the present disclosure is not limited specificembodiments described above but may be varied by those skilled in theart without departing from the subject matter of the present disclosureclaimed in the following claims. Further, these variations should not beunderstood individually from the technical spirit or perspective of thepresent disclosure.

What is claimed is:
 1. A method of transmitting a media transport streamby using an IP based transport system, the method comprising: removingsome data from media transport stream to be transmitted; forming atleast one entry box including information for reinserting the removeddata into the media transport stream; forming a mdat box including themedia transport stream from which the data is removed; and positioningand transporting a compression information box including the at leastone entry box before the mdat box.
 2. The method of claim 1, wherein theremoving comprises removing stuffing bytes from the media transportstream.
 3. The method of claim 2, wherein the entry box comprises atleast one of first information representing repeated data, secondinformation representing the position of the repeated data, and thirdinformation representing how many times data is repeated.
 4. The methodof claim 1, wherein the removing of the some data comprises removingsync bytes from the media transport stream.
 5. The method of claim 4,wherein the entry box comprises first flag information that representswhether the sync bytes are removed.
 6. The method of claim 5, whereinthe first flag information has the same value for all the entry boxesincluded in the compression information box.
 7. The method of claim 1,wherein the removing comprises removing null packets from the mediatransport stream.
 8. The method of claim 7, wherein the compressioninformation box further comprises a null packet signal box withinformation for reinserting the removed null packets into the mediatransport stream.
 9. The method of claim 8, wherein the null packetsignal box comprises a plurality of entries corresponding to a pluralityof transport packets and each of the plurality of entries comprisesfirst field information that represents whether the transport packetcorresponding to the entry is a null packet.
 10. The method of claim 1,further comprising storing a media file that includes the compressioninformation box and mdat box.
 11. A method of receiving a mediatransport stream by using an IP based transport system, the methodcomprising: sequentially receiving a compression information box thatincludes at least one entry box and an mdat box that includes mediatransport stream from which some data are removed; acquiring informationfor reinserting the removed data from the entry box; and reinserting theremoved data into the media transport stream that is included in themdat box, by using the acquired information.
 12. The method of claim 11,wherein the reinserting of the removed data comprises reinserting theremoved stuffing data into the media transport stream by sequentiallyusing two or more entry boxes according to the received order that areincluded in the compression information box.
 13. The method of claim 12,wherein the entry box comprises at least one of first informationrepresenting repeated data, second information the position of repeateddata, and third information representing how many times data isrepeated.
 14. The method of claim 11, wherein the reinserting comprises:identifying whether sync bytes are removed according to first flaginformation included in the entry box; and reinserting the removed syncbytes into the media transport stream.
 15. The method of claim 11,wherein the compression information box further comprises a null packetsignal box with information for reinserting the null packet removed fromthe media transport stream, and the null packet signal box comprises aplurality of entries corresponding to a plurality of transport packets,and each of the plurality of entries comprises first field informationrepresenting whether a transport packet corresponding to the entry is anull packet.
 16. The method of claim 15, wherein the reinsertingcomprises: identifying whether the null packet is removed, by usingfirst field information that is included in the null packet signal box;and reinserting the removed null packet into the media transport stream.17. An apparatus for transmitting a media transport stream by using anIP based transport system, the apparatus comprising: a control unitremoving some data from media transport stream to be transmitted andconfiguring a compression information box that includes at least oneentry box and a media data (mdat) box that includes media transportstream from which the data is removed; and a network interface unitpositioning and transporting the compression information box before themdat box, and wherein the entry box includes information for reinsertingthe removed data into the media transport stream.
 18. The apparatus ofclaim 17, wherein the removed data comprises at least one of a stuffingbyte and a sync byte, and wherein the entry box comprises at least oneof first information representing repeated data, second informationrepresenting the position of the repeated data, third informationrepresenting how many times data is repeated, and first flag informationrepresenting whether the sync byte is removed.
 19. The apparatus ofclaim 17, further comprising a storing unit that stores a media filethat includes the compression information box and mdat box.
 20. Anapparatus for receiving media transport stream by using an IP basedtransport system, the apparatus comprising: a network interface unitsequentially receiving a compression information box that includes atleast one entry box and a media data (mdat) box that includes mediatransport stream from which some data is removed; and a control unitacquiring information for reinserting the removed data, from the entrybox and reinserting the removed data into media transport streamincluded in the mdat box, by using the acquired information.